Does Dovecot's test authentication driver leak supplied credentials through process titles?

When validating an authentication integration locally, Dovecot's built-in test passdb allows testing without real production credentials. The passdb { driver = test } configuration and the doveadm auth test utility are documented for debugging, but it is uncertain whether the supplied username or password becomes visible outside the Dovecot process. On shared systems, a transient credential exposed in a process title or environment variable could be captured by other users.

The unresolved point is whether the test authentication path writes the username or password into the process title, environment, or log buffer in clear text, and whether that behavior is consistent across supported Dovecot releases. Administrators need to know if the test driver is safe to run on a multi-user test host without first scrubbing the command line.

Does doveadm auth test expose the supplied username or password in the process title or environment variables visible to ps? Is there a supported way to invoke the test passdb so that credential strings never appear in process listings? Which Dovecot versions have altered the handling of process titles for authentication commands?